The invention is concerned with an installation for refuelling a mobile pressure vessel, in particular a fuel tank on a vehicle, with a gaseous fuel which in particular is natural gas, having at least two intermediate stores in which the fuel may be stored at different storage pressures, and a batching device by which a refuelling equipment which may be coupled to the pressure vessel may be connected to any one of the intermediate stores in a predetermined sequence, starting with the intermediate store which exhibits the lowest storage pressure.
The invention is further concerned with a method of operation of an installation of that kind.
An installation of the aforesaid kind, known from the SULZER-BURCKHARDT publication: "Factors influencing the use of CNG as an automotive fuel", 1986, contains three groups of intermediate stores fed by a high-pressure compressor connected to a natural gas main, the natural gas being compressed into the intermediate stores of all three groups at a storage pressure of, e.g., 250 bar. The intermediate storage groups are respectively connected to the refuelling equipment according to a predetermined sequence of priorities so that the storage pressures of the individual groups decrease at different rates. The batching device of the known installation contains three electromagnetic control valves which may be energized via a processor, and via which the intermediate storage groups may be connected one at a time to the refuelling equipment. At the start of a process of refuelling, the first control valve which is opened first of all by the processor is that which is associated with the group of intermediate stores at the lowest storage pressure. When the same pressure prevails in the pressure vessel being refuelled and in the intermediate stores of this first group the first control valve is closed and the second control valve associated with the group of intermediate stores at the middle storage pressure is opened. When the pressure which prevails in the pressure vessel is the same as in the intermediate stores of this second group, the second control valve is closed and the third control valve is opened which is associated with the group of intermediate stores at the highest storage pressure. When a predetermined refuelling pressure is reached in the pressure vessel the third control valve is closed and the refuelling process is terminated. The electromagnetic control valves of the known batching device, which have to be designed for high pressure and energized each on its own, demand a relatively elaborate multiple control arrangement. In addition, at low ambient temperatures as well as through moisture the operability of control valves of that kind may become impaired.